package lab_02.test_30;

import java.util.Scanner;

public class AverageScore {

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        System.out.println();
        int a= sc.nextInt();

        System.out.println();
        int b= sc.nextInt();

        System.out.println();
        int c= sc.nextInt();

        System.out.println();
        int d= sc.nextInt();

        System.out.println((a+b+c+d)/4);
    }
}
